Men have always wanted to fly like birds. Birds can fly easily because they are light, but men's bodies are heavier.

    Men first went up into the air in balloons. These were big bags, and they were filled with gas. Hydrogen (氢气) is a useful gas for balloons. It is lighter than air. Helium is also lighter than air, but it costs a lot of money. So balloons are usually filled with hydrogen.

Balloons have to fly with the wind as they have no engines (发动机) to drive them. Later, men made airships. They are balloons with engines. They are also filled with hydrogen.

    Aircrafts (飞机) with wings now take people across the world. Powerful engines drive these machines across the sky. Some of the engines are like the engines of cars, but they are more powerful.

    There is another kind of engine, we call it the jet (喷射) engine. An English engineer invented the jet engine. At the same time, Germans were also building a jet engine. In May 1941, the English engineer's new engine was fixed in an aircraft, and the aircraft flew quite well.

    Jet engines are very powerful. Usually two to four are enough for an airplane, but some big aircraft need six. Anyone in a moving jet plane can feel the power of the engines. Jet planes can travel faster than sound. As a flying jet plane leaves its noise behind, we do not hear it until it has gone.

    You might be surprised to learn that India produces about 800 movies a year, and that number continues to grow. Just as the center of the American film industry is Hollywood, the movie center of India is Mumbai, known 1 Bombay. “Bollywood” is a combination (结合) of the 2 “Bombay” and “Hollywood”.

    Bollywood is not a physical place. Some people 3 the name, saying that it makes the industry look like a poor cousin to Hollywood. 4, Bollywood is one of the largest centers of film production in the world.

    No Bollywood movie is thought complete 5 a few songs and dances. In fact, music is an important part of Bollywood movies. Even a bad movie can still be 6 if the music is good. Because of this, music directors are sometimes more popular than actors. A Bollywood movie has five to six songs in it, often explaining what the dances mean. A film's success often 7 on the quality of such musical numbers. In some ways, Bollywood has been influencing 8 films in the western world since the 2000s.

    Bollywood may be different from Hollywood when it comes to musical style, but it is very 9 to Hollywood in several ways. Bollywood hero Shark Khan uses a gun just like Hollywood star Tom Cruise. News reporters follow Bollywood stars just as often as Hollywood stars. The personal lives of Indian actors and actresses catch the headlines, just as 10 do in the United States.

    Thang-ga(唐卡）is a special kind of painting .It was found only in Tibet,China. It started from the Tang Dynasty(唐朝). Thang-ga paintings show Tibetan people's lives. In recent years, Tang-ga paintings have caught the public's attention .At the same time,the Chinese government has also tried hard to protect the art.

    The color of Tang-ga paintings looks wonderful and special. Because of the special environment of Tibet and the excellent skills of artists, the paints(颜料) used in Thang-ga are different from other paints. They were made from minerals like gold and silver, as well as some plants. The paints were made by hand and the beautiful colors could last(持续)for hundreds of years.

    However, with the development of technology, people now use cheaper and more easily-made chemicals to make Thang-ga paints. The traditional paints used in Thang-ga paintings took a lot of work and they were made in many secret ways. Later people stopped making the paints and forgot about them. So the skills needed to make them were almost lost. The traditional Thang-ga paintings are difficult to find now.